Access system for a hub of a wind turbine

Abstract

An access system for a hub of a wind turbine, wherein the hub comprises a first flange for mounting a first rotor blade, a second flange for mounting a second rotor blade and a third flange for mounting a third rotor blade is provided. The hub comprises a first opening, a second opening and at least a third opening, each of the openings being suitable for accessing an interior of the hub from outside of the hub. The access system comprises a first ladder with a plurality of first rungs, the first ladder extending inward from the first opening, a second ladder with a plurality of second rungs, the second ladder extending inward from the second opening, and a third ladder with a plurality of third rungs, the third ladder extending inward from the third opening.

The invention claimed is: 
     
       1. An access system for a hub of a wind turbine, the hub comprising a first flange for mounting a first rotor blade, a second flange for mounting a second rotor blade, a third flange for mounting a third rotor blade, a first opening, a second opening, and at least a third opening, each of the first opening, the second opening, and the third opening being suitable for accessing an interior of the hub from an outside of the hub, the access system comprising:
 a first ladder with a plurality of first rungs, the first ladder extending inward from the first opening; 
 a second ladder with a plurality of second rungs, the second ladder extending inward from the second opening; and 
 a third ladder with a plurality of third rungs, the third ladder extending inward from the third opening; 
 wherein at least the first ladder comprises a first rail and a second rail, the second rail being parallel to the first rail; 
 wherein each rung of the plurality of first rungs extends from the first rail to the second rail, comprising a first angle between the plurality of first rungs and the first rail, and a second angle between the plurality of first rungs and the second rail; 
 wherein the first angle and the second angle are each greater than 100 degrees; 
 wherein, for each of a nine rotational hub positions, at least one part of a rung of at least one of: the first ladder, the second ladder, and the third ladder, is horizontal for a person entering the hub from an area outside the hub; 
 wherein each of the plurality of first rungs comprises a first unit, a second unit and a third unit, further wherein:
 the first unit is attached to the first rail, the first angle is built between the first rail and the first unit, the third unit is attached to the second rail, the second angle is built between the second rail and the third unit, and the second unit connects the first unit and the third unit. 
 
 
     
     
       2. The access system according to  claim 1 , wherein each of the first ladder, the second ladder, and the third ladder comprise an outer end, which is directed towards one of the first opening, the second opening, and the third opening, and an inner end, which is opposite to the outer end, and the inner ends are mechanically joined to each other. 
     
     
       3. The access system according to  claim 1 , wherein the second unit is perpendicular to the first rail. 
     
     
       4. The access system according to  claim 1 , wherein the first angle is equal to the second angle. 
     
     
       5. The access system according to  claim 1 , wherein:
 the first angle is in a range between 115 degrees and 125 degrees and/or 
 the second angle is in a range between 115 degrees and 125 degrees. 
 
     
     
       6. The access system according to  claim 1 , wherein:
 the hub comprises a first position, wherein the first rotor blade points to a first direction which is defined by a direction of a gravitational force acting on the first rotor blade, 
 the hub comprises a second position, wherein the first rotor blade points to a second direction which is rotated about 90 degrees in a counter-clockwise rotational direction with regard to the first position, 
 the hub comprises a third position, wherein the first rotor blade points to a third direction which is rotated 90 degrees in a clockwise rotational direction with regard to the first position, and for each of the first position, the second position, and the third position, a plurality of rungs are perpendicular to the direction where the first rotor blade points to. 
 
     
     
       7. The access system according to  claim 1 , wherein the wind turbine comprises a gearbox.